The present invention relates to an improved process and apparatus for detecting and removing harmful toxins, such as mycotoxins and benzpyrene (BZP), found in tobacco and tobacco products to ensure that the products are safe for human association and/or consumption. More specifically, the invention relates to a novel process and apparatus for continuously detecting, monitoring and removing harmful mycotoxins, in particular, but not limited to, aflatoxins, and benzpyrene and its precursors, during processing of tobacco for human association, consumption and use. Moreover, the novel process and apparatus provides for inhibiting production of harmful toxins in tobacco and tobacco products, and for continuous monitoring and removal of such toxins from solvent and gaseous effluent streams arising from processing tobacco.
Since at least as early as the 1980's, an increasing concern about public safety has led tobacco processors and refiners to attempt to reduce the tar content of cigarettes. It was this concern about consumer safety that resulted in research in the field of tobacco treatments for manufacturing reformulated tobacco with lower tar. U.S. Pat. No. 4,944,316 to Stuhl et al., entitled "Process for Treating Tobacco and Similar Organic Materials."
It is believed that safety initiatives by the tobacco companies, however, have only recently addressed some of the most potent carcinogens: mycotoxins. A class of mycotoxins, commonly known as aflatoxins, is one of the most potent carcinogens known to man. Eaton, David L., and John D. Groopman, The Toxicology of Aflatoxins, Academic Press, New York, 1994. Aflatoxins are estimated to be 200 times more carcinogenic than benzpyrene, the most regularly acknowledged carcinogen in tobacco smoke. Moreover, benzpyrene pre-treatment of some species has been associated with an increase in bioactivity of aflatoxins. Ma, Xinfang, Jacqueline A. Gibbons and John G. Babish, "Benzo[e]pyrene Pretreatment of Immature, Female C57BL/6J Mice Results in Increased Bioactivation of Afilatoxin B.sup.1 in Vitro." Toxicology Letters, 1991; 59: 51-58.
Additionally, aflatoxins have been shown to be profound immunosuppressants. Denning, D. W., "Aflatoxin and Outcome from Acute Lower Respiratory Infection in Children in the Philippines." Annals of Tropical Paediatrics, 1995; 15: 209-216. A 400% increase in the titers of human immunodeficiency virus (HIV) occurs when exposed to aflatoxin. Yao, Yan, Amy Hoffer, Ching-yi Chang, and Alvaro Puga, "Dioxin Activates HIV-1 Gene Expression by an Oxidative Stress Pathway Requiring a Functional Cytochrome P450 CYP1A1 Enzyme." Environmental Health Perspectives, March, 1995; 103: 366-371.
The potency of aflatoxins is further illustrated by its presence as one of the chemical agents in Iraq's arsenal of chemical weapons. See a study by Anthony H. Cordesman, co-director of the Middle East Program at the Center for Strategic and International Studies, entitled "Weapons of Mass Destruction in Iraq" (Nov. 14, 1996).
It has been observed that many tumor types found in experimental animals that are exposed to aflatoxins are the same as the tumor types found in cigarette smokers. As is well known, tobacco use has been associated with an increased incidence of many cancers, typically cancer of the lung, esophagus, mouth, throat, stomach, colon, kidney, bladder, and breast, among others. The presence of mycotoxins, such as aflatoxins, on tobacco may be a cause of the high incidence of cancer associated directly and indirectly with cigarette smoking. Dvorackova, Ivana, M. D. "Aflatoxin Inhalation and Alveolar Cell Carcinoma." British Medical Journal, Mar. 20, 1976; 691. El-Maghraby, O. M. and M. A. Abdel-Sater, "Mycoflora and Natural Occurrence of Mycotoxins from Cigarettes in Egypt." Zentralblatt fur Mikrobiologie, 1993; 148(4): 253-264.
In addition to danger to a cigarette smoker by the presence of aflatoxins in primary cigarette smoke, aflatoxins may be a special hazard in secondhand smoke. Both aflatoxins, which are dihydrobenzofurofurans, and benzpyrene, are aromatic heterocyclics, which means they are relatively stable. Therefore, although some aflatoxins present in tobacco may be combusted at the combustion temperatures that are produced when a cigarette is burnt by inhaling at one end, aflatoxins have been shown under some smoking conditions, especially idling of a burning cigarette, to survive the combustion process. Lofroth, Goran and Yngve Zebuhr, "Polychlorinated Dibenzo-p-dioxins (PCDDs) and Dibenzofurans (PCDFs) in Mainstream and Sidestream Cigarette Smoke." Bulletin of Environmental Contamination Toxicology, 1992; 48: 789-794. As secondhand smoke is often combusted at lower temperatures than primary smoke, a larger proportion of aflatoxins may remain undestroyed in secondhand smoke, posing an environmental danger to others. In at least one study, passive or secondary smoke has been linked to repeated occurrences of acute otitis media among pre-school children. Collet, J. P., et al., "Parental Smoking and Risk of Otitis Media in Pre-school Children." Canadian Journal of Public Health, July-August, 1995; 86(4): 269-273.
Inhalation of primary or secondhand smoke contaminated with aflatoxins may be inadvertently increasing titers of HIV in individuals thus exposed; for example, pregnant women with HIV, thus increasing the chances of infecting their offspring. Yao, Yan, supra; and Vlahov, David, Ph.D., et al., "Prognostic Indicators for AIDS and Infectious Disease Death in HIV-Infected Injection Drug Users: Plasma Viral Load and CD4.sup.+ Cell Count." JAMA, Jan. 7, 1998; 279 (1): 35-40.
These potent health hazards are produced by the Aspergillus and Penicillium fungi, among others, and were known to be present in tobacco and tobacco products since at least the 1960's. Pattee, Harold E., "Production of Aflatoxins by Aspergillus flavus Cultured on Flue-Cured Tobacco." Applied Microbiology, November, 1969; 18: 952-953; Welty, R. E., G. B. Lucas, J. T. Fletcher, and H. Yang, "Fungi Isolated from Tobacco Leaves and Brown-Spot Lesions Before and After Flue-Curing." Applied Microbiology, September, 1968; 16: 1309-1313; Hamilton, P. B., G. B. Lucas and R. E. Welty, "Mouse Toxicity of Fungi of Tobacco." Applied Microbiology, October, 1968; 18: 570-574.; and Welty, R. E. and G. B. Lucas, "Fungi Isolated from Flue-Cured Tobacco at Time of Sale and After Storage." Applied Microbiology, March, 1969; 17: 360-365. However, the significance and potential health hazard of aflatoxins were not considered by the tobacco industry until now. In a 1997 United States Patent to Subbiah, entitled "Method of Inhibiting Mycotoxin Production," U.S. Pat. No. 5,698,599, and assigned on its face to the R. J. Reynolds Tobacco Company, a method is disclosed for inhibiting mycotoxin production in tobacco.
Mycotoxins in general, and aflatoxins in particular, are monitored and controlled in agricultural feed and foodstuffs to minimize their impact. Current Food and Drug Administration (FDA) regulations ban use of aflatoxin-contaminated corn and grain when aflatoxin levels exceed 20 parts per billion (ppb). Similar regulations apply for other mycotoxins. Yet, due to lack of FDA authority, no regulations presently exist to mandate permissible levels of these toxins on tobacco products, both for chewing and smoking. Presently there is no regulatory oversight to ensure that tobacco and tobacco products consumed by the public are adequately screened and treated for mycotoxins, such as aflatoxins, and benzpyrene. Furthermore, there is no publicly available information which reveals that adequate measures are being taken by the tobacco industry to monitor, treat and remove these potent toxins from tobacco and tobacco products.
Treatment of tobacco to reduce such harmful toxins is of critical importance. Monitoring the production process to ensure continuous diminution is of equal importance. A failure to adequately monitor, treat and remove these harmful toxins could result in their continued presence in tobacco and tobacco products with attendant negative public health consequences.
Prior art tobacco treatment processes do not fully acknowledge or address the implications of mycotoxins (such as aflatoxins) on tobacco leaves, and therefore, the prior art processes do not adequately monitor or treat the toxins. Reformulation and reconstitution processes currently used in cigarette manufacturing appear to mimic many of the known processes for removing mycotoxins, especially aflatoxins, from agricultural products. U.S. Pat. No. 5,082,679 to Chapman, entitled "Method for Detoxifying Foodstuffs"; U.S. Pat. No. 4,962,774 to Thomasson et al., entitled "Tobacco Reconstitution Process"; U.S. Pat. No. 4,531,529 to White et al., entitled "Process for Increasing Filling Capacity of Tobacco"; and U.S. Pat. No. 4,055,674 to Yano et al., entitled "Method for the Removal of Aflatoxin from Cereals, Oil Seeds and Feedstuffs." However, these processes do not disclose continuously assaying and treating in-process tobacco to ensure adequate removal and continuous diminution of harmful toxins, such as mycotoxins and benzpyrene, from tobacco and tobacco end products.